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authorbibo,mao <bibo.mao@intel.com>2006-03-26 01:38:21 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-26 08:57:04 -0800
commit2326c77017c79fd6d55c69d8a49a57a252921bcd (patch)
tree5a2cafc7452953a4d5c8a8e8eaa0ae34fe306f74 /arch/i386/kernel
parentc6fd91f0bdcd294a0ae0ba2b2a7f7456ef4b7144 (diff)
[PATCH] kprobe handler: discard user space trap
Currently kprobe handler traps only happen in kernel space, so function kprobe_exceptions_notify should skip traps which happen in user space. This patch modifies this, and it is based on 2.6.16-rc4. Signed-off-by: bibo mao <bibo.mao@intel.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: "Keshavamurthy, Anil S" <anil.s.keshavamurthy@intel.com> Cc: <hiramatu@sdl.hitachi.co.jp> Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel')
-rw-r--r--arch/i386/kernel/kprobes.c19
1 files changed, 6 insertions, 13 deletions
diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index acdcc640a72..df1b346d36f 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -203,13 +203,14 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
{
struct kprobe *p;
int ret = 0;
- kprobe_opcode_t *addr = NULL;
- unsigned long *lp;
+ kprobe_opcode_t *addr;
struct kprobe_ctlblk *kcb;
#ifdef CONFIG_PREEMPT
unsigned pre_preempt_count = preempt_count();
#endif /* CONFIG_PREEMPT */
+ addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
+
/*
* We don't want to be preempted for the entire
* duration of kprobe processing
@@ -217,17 +218,6 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
preempt_disable();
kcb = get_kprobe_ctlblk();
- /* Check if the application is using LDT entry for its code segment and
- * calculate the address by reading the base address from the LDT entry.
- */
- if ((regs->xcs & 4) && (current->mm)) {
- lp = (unsigned long *) ((unsigned long)((regs->xcs >> 3) * 8)
- + (char *) current->mm->context.ldt);
- addr = (kprobe_opcode_t *) (get_desc_base(lp) + regs->eip -
- sizeof(kprobe_opcode_t));
- } else {
- addr = (kprobe_opcode_t *)(regs->eip - sizeof(kprobe_opcode_t));
- }
/* Check we're not actually recursing */
if (kprobe_running()) {
p = get_kprobe(addr);
@@ -579,6 +569,9 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
struct die_args *args = (struct die_args *)data;
int ret = NOTIFY_DONE;
+ if (args->regs && user_mode(args->regs))
+ return ret;
+
switch (val) {
case DIE_INT3:
if (kprobe_handler(args->regs))